When animals are given cocaine or amphetamine, CART mRNA is increased in brain regions associated with the addicting properties of these drugs. Accordingly, we have begun an intensive study of CART mRNA and its products. We have prepared antibodies against CART peptides and shown that CART peptides are, indeed, formed in the brain and found in the same neurones that contain CART mRNA. We are beginning to inject CART peptides to measure their behavioral effects.